Human Survival Genes Pinpointed

Feb. 5, 2008 -- Scientists have found more than 500 genes that account for variations across human populations, including skin color, height, and vulnerability to disease, according to a study released Sunday.

By comparing millions of fragments of genetic code from individuals in four groups -- from Nigeria, China, Japan and northwestern Europe -- they showed that natural selection has played a key role in these differences, according to the study.

The findings hold particular promise for understanding the genetic underpinning of certain diseases.

For example, the researchers, led by Lluis Quintana-Murci of France's National Center for Scientific Research, pinpointed the tiny genetic variation in the CR1 gene that has made 85 percent of Africans highly resistant to malaria.

Most other populations in the world do not share this variant, and are thus more susceptible to the mosquito-borne disease.

Other genetic variations -- called single nucleotide polymorphisms, or SNPs (pronounced "snips") -- identified by Quintana-Murci and his team could help explain why rates of diabetes, obesity and hypertension differ from one region to another.

Once the specific bit of genetic code responsible for a predisposition to a certain illness or condition has been identified, scientists can then set about trying to find a drug to treat it.

SNPs occur when one of the four chemical building blocks of DNA varies in a particular segment of DNA as compared to other members of the same species.